Organometallic compound, organic light-emitting device including the organometallic compound, and diagnostic composition including the organometallic compound

ABSTRACT

An organometallic compound represented by Formula 1: 
     
       
         
         
             
             
         
       
     
     wherein, in Formula 1, groups and variables are the same as described in the specification.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No. 10-2016-0108379, filed on Aug. 25, 2016, in the Korean Intellectual Property Office, and all the benefits accruing therefrom under 35 U.S.C. §119, the content of which is incorporated herein in its entirety by reference.

BACKGROUND 1. Field

One or more embodiments relate to an organometallic compound, an organic light-emitting device including the organometallic compound, and a diagnostic composition including the organometallic compound.

2. Description of the Related Art

Organic light-emitting devices are self-emission devices that produce full-color images, and also have better characteristics in terms of viewing angles, response time, luminance, driving voltage, and response speed.

In an example, an organic light-emitting device includes an anode, a cathode, and an organic layer disposed between the anode and the cathode, wherein the organic layer includes an emission layer. A hole transport region may be disposed between the anode and the emission layer, and an electron transport region may be disposed between the emission layer and the cathode. Holes provided from the anode may move toward the emission layer through the hole transport region, and electrons provided from the cathode may move toward the emission layer through the electron transport region. The holes and the electrons recombine in the emission layer to produce excitons. These excitons transition from an excited state to a ground state, thereby generating light.

Meanwhile, photoluminescent compounds may be used to monitor, sense, or detect a biological material such as a cell protein. Examples of such photoluminescent compounds include a phosphorescent photoluminescent compound.

Various types of organic light emitting devices are known. However, there still remains a need in OLEDs having low driving voltage, high efficiency, high brightness, and long lifespan.

SUMMARY

One or more embodiments include a novel organometallic compound, an organic light-emitting device including the organometallic compound, and a diagnostic composition including the organometallic compound.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

According to one or more embodiments, an organometallic compound is represented by Formula 1:

wherein, in Formula 1,

M may be beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt), or gold (Au),

X₁ may be O or S, and a bond between X₁ and M may be a covalent bond,

i) X₂ and X₄ may be N, a bond between X₂ and M and a bond between X₄ and M may be a coordinate bond, X₃ may be C, and a bond between X₃ and M may be a covalent bond; ii) X₂ and X₃ may be N, a bond between X₂ and M and a bond between X₃ and M may be a coordinate bond, X₄ may be C, and a bond between X₄ and M may be a covalent bond; or iii) X₃ and X₄ may be N, a bond between X₃ and M and a bond between X₄ and M may be a coordinate bond, X₂ may be C, and a bond between X₂ and M may be a covalent bond,

Y₁ to Y₇ may each independently be C or N,

Y₈ and Y₉ may each independently be C, N, O, or S,

a bond between Y₁ and Y₈, a bond between Y₁ and Y₂, a bond between X₂ and Y₃, a bond between X₂ and Y₄, a bond between X₃ and Y₅, a bond between X₃ and Y₆, a bond between X₄ and Y₇, and a bond between X₄ and Y₉ may each independently be a single bond or a double bond,

CY₁, CY₂, and CY₄ may each independently be selected from a C₅-C₃₀ carbocyclic group and a C₁-C₃₀ heterocyclic group, provided that CY₂ is not an azadibenzofuran group, an azadibenzothiophene group, an azadibenzoselenophene group, an azacarbazole group, an azafluorene group, and an azadibenzosilole group, which each include at least one N as a ring-forming atom,

CY₃ may be selected from:

a dibenzofuran group, a dibenzothiophene group, a dibenzoselenophene group, a carbazole group, a fluorene group, and a dibenzosilole group; and

an azadibenzofuran group, an azadibenzothiophene group, an azadibenzoselenophene group, an azacarbazole group, an azafluorene group, and an azadibenzosilole group, which each include at least one N as a ring-forming atom,

T₁ to T₃ may each independently be selected from *—O—*′, *—S—*′, *—C(R₅)(R₆)—*′, *—C(R₅)═*′, *═C(R₅)—*′, *—C(R₅)═C(R₆)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—Si(R₅)(R₆)—*′, *—Ge(R₅)(R₆)—*′, *—B(R₅)—*′, *—N(R₅)—*′, and *—P(R₅)—*′

R₅ and R₆ may optionally be linked via a first linking group to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

b1 to b3 may each independently be 0, 1, 2, or 3, wherein when b1 is zero, *-(T₁)_(b1)-*′ may be a single bond, when b2 is zero, *-(T₂)_(b2)-*′ may be a single bond, and when b3 is zero, *-(T₃)_(b3)-*′ may be a single bond,

R₁ to R₆ may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), —P(═O)(Q₈)(Q₉), and —P(Q₈)(Q₉),

a1 to a4 may each independently be 0, 1, 2, 3, 4, or 5,

two of groups R₁ in the number of a1 may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

two of groups R₂ in the number of a2 may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

two of groups R₃ in the number of a3 may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

two of groups R₄ in the number of a4 may optionally be linked to a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

two or more neighboring groups selected from R₁ to R₄ may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

one of R₅ and R₆ may optionally be linked to R₃ to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

one of R₅ and R₆ may optionally be linked to R₄ to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, and

at least one substituent selected from a substituent(s) of the substituted C₅-C₃₀ carbocyclic group, the substituted C₁-C₃₀ heterocyclic group, the substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —Ge(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), —P(═O)(Q₁₈)(Q₁₉), and —P(Q₁₈)(Q₁₉);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —Ge(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), —P(═O)(Q₂₈)(Q₂₉), and —P(Q₂₈)(Q₂₉); and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —Ge(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), P(═O)(Q₃₈)(Q₃₉), and —P(Q₃₈)(Q₃₉),

wherein Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with at least one of a C₁-C₆₀ alkyl group and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.

According to one or more embodiments, an organic light-emitting device includes:

a first electrode;

a second electrode; and

an organic layer disposed between the first electrode and the second electrode,

wherein the organic layer includes an emission layer, and

wherein the organic layer may include at least one of the organometallic compounds.

The organometallic compound in the emission may act as a dopant.

According to one or more embodiments, a diagnostic composition includes at least one of the organometallic compounds represented by Formula 1.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic view of an organic light-emitting device according to an embodiment;

FIG. 2 is a graph of photoluminescent intensity (arbitrary units, a. u.) versus wavelength (nanometers, nm) showing a photoluminescent spectrum of Compound 1; and

FIG. 3 is a graph of photoluminescent intensity (arbitrary units, a. u.) versus wavelength (nanometers, nm) showing a photoluminescent spectrum of Compound 2.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

It will be understood that when an element is referred to as being “on” another element, it can be directly in contact with the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present embodiments.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The term “or” means “and/or.” It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this general inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present claims.

“About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within +30%, 20%, 10%, 5% of the stated value.

An organometallic compound according to an embodiment may be represented by Formula 1:

wherein M in Formula 1 may be beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt), or gold (Au).

For example, M in Formula 1 may be platinum (Pt), but embodiments of the present disclosure are not limited thereto.

The organometallic compound represented by Formula 1 may be a neutral compound which does not consist of an ion pair of a cation and an anion.

In Formula 1, X₁ may be O or S, and a bond between X₁ and M may be a covalent bond.

In Formula 1, i) X₂ and X₄ may be N, a bond between X₂ and M and a bond between X₄ and M may be a coordinate bond, X₃ may be C, and a bond between X₃ and M may be a covalent bond; ii) X₂ and X₃ may be N, a bond between X₂ and M and a bond between X₃ and M may be a coordinate bond, X₄ may be C, and a bond between X₄ and M may be a covalent bond; or iii) X₃ and X₄ may be N, a bond between X₃ and M and a bond between X₄ and M may be a coordinate bond, X₂ may be C, and a bond between X₂ and M may be a covalent bond.

In one or more embodiments, in Formula 1, X₂ and X₄ may be N, a bond between X₂ and M and a bond between X₄ and M may be a coordinate bond, X₃ may be C, and a bond between X₃ and M may be a covalent bond, but embodiments of the present disclosure are not limited thereto.

Y₁ to Y₇ in Formula 1 may each independently be C or N.

Y₈ and Y₉ in Formula 1 may each independently be C, N, O, or S.

In one more embodiments, in Formula 1, X₂ and X₄ may be N, a bond between X₂ and M and a bond between X₄ and M may be a coordinate bond, X₃ may be C, a bond between X₃ and M may be a covalent bond, and Y₁ to Y₇ may be C, but embodiments of the present disclosure are not limited thereto.

In Formula 1, a bond between Y₁ and Y₈, a bond between Y₁ and Y₂, a bond between X₂ and Y₃, a bond between X₂ and Y₄, a bond between X₃ and Y₅, a bond between X₃ and Y₆, a bond between X₄ and Y₇, and a bond between X₄ and Y₉ may each independently be a single bond or a double bond.

CY₁, CY₂, and CY₄ in Formula 1 may each independently be selected from a C₅-C₃₀ carbocyclic group and a C₁-C₃₀ heterocyclic group, provided that CY₂ is not an azadibenzofuran group, an azadibenzothiophene group, an azadibenzoselenophene group, an azacarbazole group, an azafluorene group, or an azadibenzosilole group, which each include at least one N as a ring-forming atom.

For example, CY₁, CY₂, and CY₄ in Formula 1 may each independently be selected from 6-membered cyclic groups.

In one or more embodiments, in Formula 1,

CY₁ and CY₄ may each independently be selected from a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a 1,2,3,4-tetrahydronaphthalene group, a furan group, a thiophene group, a selenophene group, a pyrrole group, a cyclopentadiene group, a silole group, a benzofuran group, a benzothiophene group, a benzoselenophene group, an indole group, an indene group, a benzosilole group, a dibenzofuran group, a dibenzothiophene group, a dibenzoselenophene group, a carbazole group, a fluorene group, a dibenzosilole group, an azadibenzofuran group, an azadibenzothiophene group, an azadibenzoselenophene group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a phenanthroline group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzoxadiazole group, a benzothiadiazole group, a 5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinoline group, and

CY₂ may be selected from a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a 1,2,3,4-tetrahydronaphthalene group, a furan group, a thiophene group, a selenophene group, a pyrrole group, a cyclopentadiene group, a silole group, a benzofuran group, a benzothiophene group, a benzoselenophene group, an indole group, an indene group, a benzosilole group, a dibenzofuran group, a dibenzothiophene group, a dibenzoselenophene group, a carbazole group, a fluorene group, a dibenzosilole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a phenanthroline group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an iso-oxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzoxadiazole group, a benzothiadiazole group, a 5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinoline group, but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, in Formula 1,

CY₁ and CY₄ may each independently be selected from a benzene group, a naphthalene group, a 1,2,3,4-tetrahydronaphthalene group, a dibenzofuran group, a dibenzothiophene group, a dibenzoselenophene group, a carbazole group, a fluorene group, a dibenzosilole group, an azadibenzofuran group, an azadibenzothiophene group, an azadibenzoselenophene group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, and a quinazoline group, and

CY₂ may be selected from a benzene group, a naphthalene group, a 1,2,3,4-tetrahydronaphthalene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, and a quinazoline group, but embodiments of the present disclosure are not limited thereto.

CY₃ in Formula 1 may be selected from:

a dibenzofuran group, a dibenzothiophene group, a dibenzoselenophene group, a carbazole group, a fluorene group, and a dibenzosilole group; and

an azadibenzofuran group, an azadibenzothiophene group, an azadibenzoselenophene group, an azacarbazole group, an azafluorene group, and an azadibenzosilole group, which each include at least one N as a ring-forming atom.

“An azabenzofuran, an azabenzothiophene, an azabenzoselenophene, an azaindole, an azaindene, an azabenzosilole, an azadibenzofuran, an azadibenzothiophene, an azadibenzoselenophene, an azacarbazole, an azafluorene, and an azadibenzosilole” as described herein may mean hetero rings that respectively have the same backbones as “a benzofuran, a benzothiophene, a benzoselenophene, an indole, an indene, a benzosilole, a dibenzofuran, a dibenzothiophene, a dibenzoselenophene, a carbazole, a fluorene, and a dibenzosilole”, provided that at least one of carbons forming rings thereof is substituted with nitrogen.

T₁ to T₃ in Formula 1 may each independently be selected from *—O—*′, *—S—*′, *—C(R₅)(R₆)—*′, *—C(R₅)═*′, *═C(R₅)—*′, *—C(R₅)═C(R₆)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—Si(R₅)(R₆)—*′, *—Ge(R₅)(R₆)—*′, *—B(R₅)—*′, *—N(R₅)—*′, and *—P(R₅)—*′. R₅ and R₆ are the same as described below.

In one more embodiments, T₁ to T₃ in Formula 1 may each independently be selected from *—O—*′, *—S—*′, *—C(R₅)(R₆)—*′, *—Si(R₅)(R₆)—*′, *—N(R₅)—*′, and *—P(R₅)—*′, but embodiments of the present disclosure are not limited thereto.

R₅ and R₆ may optionally be linked via a first linking group to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group (for example, a C₅ or C₆ 5-membered to 7-membered cyclic group; or a C₅ or C₆ 5-membered to 7-membered cyclic group, substituted with at least one selected from deuterium, a cyano group, —F, a C₁-C₁₀ alkyl group, and a C₆-C₁₄ aryl group).

In one more embodiments, T₁ to T₃ may each independently be selected from *—C(R₅)(R₆)—*′, *—Si(R₅)(R₆)—*′, and *—Ge(R₅)(R₆)—*′,

R₅ and R₆ may be linked via a first linking group,

the first linking group may be selected from a single bond, *—O—*′, *—S—*′, *—C(R₉)(R₁₀)—*′, *—C(R₉)═*′, *═C(R₉)—*′, *—C(R₉)═C(R₁₀)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—Si(R₉)(R₁₀)—*′, *—Ge(R₉)(R₁₀)—*′, *—B(R₉)—*′, *—N(R₉)—*′, and *—P(R₉)—*′,

R₉ and R₁₀ are each independently the same as described above in connection with R₅, and

* and *′ each indicate a binding site to a neighboring atom, but embodiments of the present disclosure are not limited thereto.

b1, b2, and b3 in Formula 1 respectively indicate the number of groups Ti, the number of groups T₂, and the number of groups T₃ and may each independently be 0, 1, 2, or 3. When b1 is zero, *-(T₁)_(b1)-*′ may be a single bond, when b2 is zero, *-(T₂)_(b2)-*′ may be a single bond, and when b3 is zero, *-(T₃)_(b3)-*′ may be a single bond.

In one or more embodiments, in Formula 1,

b1, b2, and b3 may each be zero;

b1 may be one, and b2 and b3 may each be zero;

b2 may be one, and b1 and b3 may each be zero; or

b3 may be one, and b1 and b2 may each be zero, but embodiments of the present disclosure are not limited thereto.

R₁ to R₆ in Formula 1 may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), —P(═O)(Q₈)(Q₉), and —P(Q₈)(Q₉).

For example, R₁ to R₆ may each independently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, —SF₅, C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, and a pyrimidinyl group;

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group;

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅); and

—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), —P(═O)(Q₈)(Q₉), and —P(Q₈)(Q₉),

wherein Q₁ to Q₉ and Q₃₃ to Q₃₅ may each independently be selected from:

—CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and —CD₂CDH₂;

an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group; and

an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group, each substituted with at least one selected from deuterium, a C₁-C₁₀ alkyl group, and a phenyl group.

In one more embodiments, R₁ to R₆ may each independently be selected from:

hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, an iso-hexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an iso-heptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an iso-octyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an iso-nonyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an iso-decyl group, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group;

a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, an iso-hexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an iso-heptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an iso-octyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an iso-nonyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an iso-decyl group, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group, each substituted with at least one selected from deuterium, —F, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a cyano group, a nitro group, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group; and

—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉),

wherein Q₁ to Q₉ are each independently the same as described above.

In one or more embodiments, R₁ to R₆ may each independently be selected from hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, groups represented by Formulae 9-1 to 9-19, groups represented by Formulae 10-1 to 10-46, and —Si(Q₃)(Q₄)(Q₅) (wherein Q₃ to Q₅ are the same as described above), but embodiments of the present disclosure are not limited thereto:

* in Formulae 9-1 to 9-19 and 10-1 to 10-46 indicates a binding site to a neighboring atom.

a1, a2, a3, and a4 in Formula 1 respectively indicate the number of groups R₁, the number of groups R₂, the number of groups R₃, the number of groups R₄ and may each independently be 0, 1, 2, 3, 4, or 5. When a1 is two or more, two or more groups R₁ may be identical to or different from each other, when a2 is two or more, two or more groups R₂ may be identical to or different from each other, when a3 is two or more, two or more groups R₃ may be identical to or different from each other, and when a4 is two or more, two or more groups R₄ may be identical to or different from each other, but embodiments of the present disclosure are not limited thereto.

In Formula 1, two of groups R₁ in the number of a1 may optionally be linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two of groups R₂ in the number of a2 may optionally be linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two of groups R₃ in the number of a3 may optionally be linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two of groups R₄ in the number of a4 may optionally be linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two or more neighboring groups selected from R₁ to R₄ may optionally be linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, one of R₅ and R₆ may optionally be linked to R₃ to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, and one of R₅ and R₆ may optionally be linked to R₄ to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group.

For example, a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, which may be formed by i) optionally linking two of groups R₁ in the number of a1, ii) optionally linking two of groups R₂ in the number of a2, iii) optionally linking two of groups R₃ in the number of a3, iv) optionally linking two of groups R₄ in the number of a4, v) optionally linking two or more neighboring groups selected from R₁ to R₄, vi) optionally linking one of R₅ and R₆ to R₃, and vii) optionally linking one of R₅ and R₆ to R₄ in Formula 1, may be selected from:

a pentadiene group, a cyclohexane group, a cycloheptane group, an adamantane group, a bicyclo-heptane group, a bicyclo-octane group, a benzene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a naphthalene group, an anthracene group, a tetracene group, a phenanthrene group, a dihydronaphthalene group, a phenalene group, a benzofuran group, a benzothiophene group, a benzoselenophene group, an indole group, an indene group, a benzosilole group, an azabenzofuran group, an azabenzothiophene group, an azabenzoselenophene group, an azaindole group, an azaindene group, and an azabenzosilole group; and

a pentadiene group, a cyclohexane group, a cycloheptane group, an adamantane group, a bicyclo-heptane group, a bicyclo-octane group, a benzene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a naphthalene group, an anthracene group, a tetracene group, a phenanthrene group, a dihydronaphthalene group, a phenalene group, a benzofuran group, a benzothiophene group, a benzoselenophene group, an indole group, an indene group, a benzosilole group, an azabenzofuran group, an azabenzothiophene group, an azabenzoselenophene group, an azaindole group, an azaindene group, and an azabenzosilole group, each substituted with at least one R_(1a), but embodiments of the present disclosure are not limited thereto.

R_(1a) is the same as described above in connection with R₁.

In one or more embodiments, a moiety represented by

in Formula 1 may be selected from groups represented by Formulae CY1-1 to CY1-16:

In Formulae CY1-1 to CY1-16,

X₁₁ may be N or C(R₁₁), X₁₂ may be N or C(R₁₂), X₁₃ may be N or C(R₁₃), X₁₄ may be N or C(R₁₄), X₁₅ may be N or C(R₁₅), X₁₆ may be N or C(R₁₆), X₁₇ may be N or C(R₁₇), and X₁₈ may be N or C(R₁₈),

X₁₉ may be C(R_(19a))(R_(19b)), N(R₁₉), O, S, Se, or Si(R_(19a))(R_(19b)),

R₁₁ to R₁₉ and R_(19a) to R_(19c) are each independently the same as described above in connection with R₁, and

* and *′ each indicate a binding site to a neighboring atom.

For example, in Formulae CY1-1 to CY1-16, X₁₁ may be C(R₁₁), X₁₂ may be C(R₁₂), X₁₃ may be C(R₁₃), X₁₄ may be C(R₁₄), X₁₅ may be C(R₁₅), X₁₆ may be C(R₁₆), X₁₇ may be C(R₁₇), and X₁₈ may be C(R₁₈), but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, a moiety represented by in

Formula 1 may be selected from groups represented by Formulae CY2-1 to CY2-11:

In Formulae CY2-1 to CY2-11,

X₂₁ may be N or C(R₂₁), X₂₂ may be N or C(R₂₂), X₂₃ may be N or C(R₂₃), X₂₄ may be N or C(R₂₄), X₂₅ may be N or C(R₂₅), X₂₆ may be N or C(R₂₆), and X₂₇ may be N or C(R₂₇),

X₂₉ may be C(R_(29a))(R_(29b)), N(R₂₉), O, S, Se, or Si(R_(29a))(R_(29b)),

R₂₁ to R₂₉, R_(29a), and R_(29b) are each independently the same as described above in connection with R₂, and

*, *′, and, *″ each indicate a binding site to a neighboring atom.

For example, in Formulae CY2-1 to CY2-11, X₂₁ may be C(R₂₁), X₂₂ may be C(R₂₂), X₂₃ may be C(R₂₃), X₂₄ may be C(R₂₄), X₂₅ may be C(R₂₅), X₂₆ may be C(R₂₆), and X₂₇ may be C(R₂₇), but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, a moiety represented by

in Formula 1 may be selected from groups represented by Formulae CY3-1 to CY3-8:

In Formulae CY3-1 to CY3-8,

X₃₁ may be N or C(R₃₁), X₃₃ may be N or C(R₃₃), X₃₄ may be N or C(R₃₄), X₃₅ may be N or C(R₃₅), X₃₆ may be N or C(R₃₆), and X₃₇ may be N or C(R₃₇),

X₃₉ may be C(R_(39a))(R_(39b)), N(R₃₉), O, S, Se, or Si(R_(39a))(R_(39b)),

R₃₁, R₃₃ to R₃₇, R₃₉, R_(39a), and R_(39b) are each independently the same as described above in connection with R₃, and

*, *′, and *″ each indicate a binding site to a neighboring atom.

For example, in Formulae CY3-1 to CY3-8, X₃₁ may be C(R₃₁), X₃₃ may be C(R₃₃), X₃₄ may be C(R₃₄), X₃₅ may be C(R₃₅), X₃₆ may be C(R₃₆), and X₃₇ may be C(R₃₇), but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, a moiety represented by

in Formula 1 may be selected from groups represented by Formulae CY4-1 to CY4-8:

In Formulae CY4-1 to CY4-8,

X₄₁ may be N or C(R₄₁), X₄₂ may be N or C(R₄₂), X₄₃ may be N or C(R₄₃), X₄₄ may be N or C(R₄₄), X₄₅ may be N or C(R₄₅), X₄₆ may be N or C(R₄₆), X₄₇ may be N or C(R₄₇), and X₄₈ may be N or C(R₄₈),

R₄₁ to R₄₈ are each independently the same as described above in connection with R₄, and

* and *′ each indicate a binding site to a neighboring atom.

For example, in Formulae CY4-1 to CY4-8, X₄₁ may be C(R₄₁), X₄₂ may be C(R₄₂), X₄₃ may be C(R₄₃), X₄₄ may be C(R₄₄), X₄₅ may be C(R₄₅), X₄₆ may be C(R₄₆), X₄₇ may be C(R₄₇), and X₄₈ may be C(R₄₈), but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, in Formula 1, a moiety represented by

may be selected from groups represented by Formulae CY1-1 and CY1-5 to CY1-10,

a moiety represented by

may be selected from groups represented by Formulae CY2-1 to CY2-7,

a moiety represented by

may be selected from groups represented by Formulae CY3-1 to CY3-4, and

a moiety represented by

may be a group represented by Formula CY4-1, but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, the organometallic compound may be represented by one selected from Formulae 1-1 to 1-4:

wherein, in Formulae 1-1 to 1-4,

M, X₁, T₁ to T₃, and b1 to b3 are each independently the same as described above,

X₁₁ may be N or C(R₁₁), X₁₂ may be N or C(R₁₂), X₁₃ may be N or C(R₁₃), and X₁₄ may be N or C(R₁₄),

X₂₁ may be N or C(R₂₁), X₂₂ may be N or C(R₂₂), and X₂₃ may be N or C(R₂₃),

X₃₁ may be N or C(R₃₁), X₃₃ may be N or C(R₃₃), X₃₄ may be N or C(R₃₄), X₃₅ may be N or C(R₃₅), X₃₆ may be N or C(R₃₆), and X₃₇ may be N or C(R₃₇),

X₃₉ may be C(R_(39a))(R_(39b)), N(R₃₉), O, S, Se, or Si(R_(39a))(R_(39b)),

X₄₁ may be N or C(R₄₁), X₄₂ may be N or C(R₄₂), X₄₃ may be N or C(R₄₃), and X₄₄ may be N or C(R₄₄),

R₁₁ to R₁₄ are each independently the same as described above in connection with R₁, and two of R₁₁ to R₁₄ may optionally be linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

R₂₁ to R₂₃ are each independently the same as described above in connection with R₂, and two of R₂₁ to R₂₃ may optionally be linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

R₃₁, R₃₃, R₃₄ to R₃₇, R₃₉, R_(39a), and R_(39b) are each independently the same as described above in connection with R₃, and two of R₃₄ to R₃₇ may optionally be linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, and

R₄₁ to R₄₄ are each independently the same as described above in connection with R₄, two of R₄₁ to R₄₄ may optionally be linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group.

For example, in Formulae 1-1 to 1-4, X₁₁ may be C(R₁₁), X₁₂ may be C(R₁₂), X₁₃ may be C(R₁₃), X₁₄ may be C(R₁₄), X₂₁ may be N or C(R₂₁), X₂₂ may be C(R₂₂), X₂₃ may be C(R₂₃), X₃₁ may be C(R₃₁), X₃₃ may be C(R₃₃), X₃₄ may be C(R₃₄), X₃₅ may be C(R₃₅), X₃₆ may be C(R₃₆), X₃₇ may be C(R₃₇), X₄₁ may be C(R₄₁), X₄₂ may be C(R₄₂), X₄₃ may be C(R₄₃), and X₄₄ may be C(R₄₄), but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, in Formulae 1-1 to 1-4, X₁₁ may be C(R₁₁), X₁₂ may be C(R₁₂), X₁₃ may be C(R₁₃), X₁₄ may be C(R₁₄), X₂₁ may be N or C(R₂₁), X₂₂ may be C(R₂₂), X₂₃ may be C(R₂₃), X₃₁ may be C(R₃₁), X₃₃ may be C(R₃₃), X₃₄ may be N, X₃₅ may be C(R₃₅), X₃₆ may be C(R₃₆), X₃₇ may be C(R₃₇), X₄₁ may be C(R₄₁), X₄₂ may be C(R₄₂), X₄₃ may be C(R₄₃), and X₄₄ may be C(R₄₄), but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, in Formulae 1-1 to 1-4, i) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group formed by optionally linking two of R₁₁ to R₁₄ with each other, ii) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group formed by optionally linking two of R₂₁ to R₂₃ with each other, iii) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group formed by optionally linking two of R₃₄ to R₃₇ with each other, and iv) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group formed by optionally linking two of R₄₁ to R₄₄ with each other may each independently be selected from:

a pentadiene group, a cyclohexane group, a cycloheptane group, an adamantane group, a biyclo-heptane group, a bicyclo-octane group, a benzene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a naphthalene group, an anthracene group, a tetracene group, a phenanthrene group, a dihydronaphthalene group, a phenalene group, a benzofuran group, a benzothiophene group, a benzoselenophene group, an indole group, an indene group, a benzosilole group, an azabenzofuran group, an azabenzothiophene group, an azabenzoselenophene group, an azaindole group, an azaindene group, and an azabenzosilole group; and

a pentadiene group, a cyclohexane group, a cycloheptane group, an adamantane group, a bicyclo-heptane group, a bicyclo-octane group, a benzene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a naphthalene group, an anthracene group, a tetracene group, a phenanthrene group, a dihydronaphthalene group, a phenalene group, a benzofuran group, a benzothiophene group, a benzoselenophene group, an indole group, an indene group, a benzosilole group, an azabenzofuran group, an azabenzothiophene group, an azabenzoselenophene group, an azaindole group, an azaindene group, and an azabenzosilole group, each substituted with at least one R_(1a),

but embodiments of the present disclosure are not limited thereto.

R_(1a) is the same as described above in connection with R₁.

In one or more embodiments, in Formula 1-1 to 1-4, T₃ may be *—N(R₅)—*′, b3 may be one, X₄₁ may be C(R₄₁), and R₅ and R₄₁ may be linked via a single bond (for example, see Formula 1(1)).

In one or more embodiments, the organometallic compound may be represented by one selected from Formulae 1(1) and 1(2):

In Formulae 1(1) and 1(2),

M, X₁ to X₄, Y₁ to Y₉, CY₁ to CY₄, T₁ to T₃, b1 to b3, R₁ to R₄, and a1 to a4 are each independently the same as described above,

X₄₂ may be N or C(R₄₂), X₄₃ may be N or C(R₄₃), and X₄₄ may be N or C(R₄₄),

R₄₂ to R₄₄ are each independently the same as described above in connection with R₄, and two of R₄₂ to R₄₄ may optionally be linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

CY₅ and CY₆ may each independently be a C₅-C₃₀ carbocyclic group or a C₁-C₃₀ heterocyclic group,

R₅₁ and R₆₁ are each independently the same as described above in connection with R₁,

a51 and a61 may each independently be 0, 1, 2, or 3,

T₄ may be C, Si, or Ge,

T₅ may be selected from a single bond, *—O—*′, *—S—*′, *—C(R₇)(R₈)—*′, *—C(R₇)=*′, *═C(R₇)—*′, *—C(R₇)═C(R₈)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—Si(R₇)(R₈)—*′, *—Ge(R₇)(R₈)—*′, *—B(R₇)—*′, *—N(R₇)—*′, and *—P(R₈)—*′,

R₇ and R₈ are each independently the same as described above in connection with R₅, and

* and *′ each indicate a binding site to a neighboring atom.

For example, in Formula 1(1), X₄₂ may be C(R₄₂), X₄₃ may be C(R₄₃), and X₄₄ may be C(R₄₄), but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, i) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group formed by optionally linking two of R₄₂ to R₄₄ with each other, ii) CY₅, and iii) CY₆ may each independently be selected from:

a pentadiene group, a cyclohexane group, a cycloheptane group, an adamantane group, a bicyclo-heptane group, a bicyclo-octane group, a benzene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a naphthalene group, an anthracene group, a tetracene group, a phenanthrene group, a dihydronaphthalene group, a phenalene group, a benzofuran group, a benzothiophene group, a benzoselenophene group, an indole group, an indene group, a benzosilole group, an azabenzofuran group, an azabenzothiophene group, an azabenzoselenophene group, an azaindole group, an azaindene group, and an azabenzosilole group; and

a pentadiene group, a cyclohexane group, a cycloheptane group, an adamantane group, a bicyclo-heptanes group, a bicyclo-octane group, a benzene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a naphthalene group, an anthracene group, a tetracene group, a phenanthrene group, a dihydronaphthalene group, a phenalene group, a benzofuran group, a benzothiophene group, a benzoselenophene group, an indole group, an indene group, a benzosilole group, an azabenzofuran group, an azabenzothiophene group, an azabenzoselenophene group, an azaindole group, an azaindene group, and an azabenzosilole group, each substituted with at least one R_(1a),

but embodiments of the present disclosure are not limited thereto.

R_(1a) is the same as described above in connection with R₁.

The organometallic compound may be selected from Compounds 1 to 11, but embodiments of the present disclosure are not limited thereto:

CY₃ in Formula 1 may be selected from: a dibenzofuran group, a dibenzothiophene group, a carbazole group, a fluorene group, and an azadibenzosilole group; and an azadibenzofuran group, an azadibenzothiophene group, an azacarbazole group, an azafluorene group, and an azadibenzosilole group, which each include at least one N as a ring-forming atom. Therefore, since a rigidity of a luminophore in the organometallic compound is increased, a vibronic-process of the luminophore may be decreased due to the increased rigidity and a full-width at half maximum (FWHM) of a photoluminescent spectrum in the organometallic compound may be decreased.

For example, a highest occupied molecular orbital (HOMO) energy level, a lowest unoccupied molecular orbital (LUMO) energy level, and a triplet (T₁) energy level of Compounds 1 to 6 were evaluated by a density functional theory (DFT) method of a Gaussian program (the structure was optimized at a B3LYP, 6-31G(d,p) level). Evaluation results thereof are shown in Table 1.

TABLE 1 Compound No. HOMO (eV) LUMO (eV) T₁ energy level (eV) 1 −4.812 −1.838 2.215 2 −4.692 −1.515 2.394 3 −4.797 −1.765 2.280 4 −4.664 −1.589 2.280 5 −4.719 −1.502 2.390 6 −4.698 −1.463 2.410

From Table 1, it can be seen that the organometallic compound represented by Formula 1 has electrical characteristics suitable for use in an electronic device, for example, for use as a dopant for an organic light-emitting device.

Synthesis methods of the organometallic compound represented by Formula 1 may be recognizable by one of ordinary skill in the art by referring to Synthesis Examples provided below.

The organometallic compound represented by Formula 1 is suitable for use in an organic layer of an organic light-emitting device, for example, for use as a dopant in an emission layer of the organic layer. Thus, another aspect provides an organic light-emitting device that includes:

a first electrode;

a second electrode; and

an organic layer that is disposed between the first electrode and the second electrode, wherein the organic layer includes an emission layer and at least one of the organometallic compounds represented by Formula 1.

The organic light-emitting device may have, due to the inclusion of an organic layer including the organometallic compound represented by Formula 1, a low driving voltage, high photoluminescent efficiency, high power efficiency, high quantum efficiency, a long lifespan, a low roll-off ratio, and excellent color purity.

The organometallic compound of Formula 1 may be used between a pair of electrodes of an organic light-emitting device. For example, the organometallic compound represented by Formula 1 may be included in the emission layer. In this regard, the organometallic compound may act as a dopant, and the emission layer may further include a host (that is, in the emission layer, an amount of the organometallic compound represented by Formula 1 is smaller than an amount of the host).

The expression “(an organic layer) includes at least one of organometallic compounds” as used herein may include an embodiment in which “(an organic layer) includes identical organometallic compounds represented by Formula 1” and an embodiment in which “(an organic layer) includes two or more different organometallic compounds represented by Formula 1.”

For example, the organic layer may include, as the organometallic compound, only Compound 1. In this regard, Compound 1 may be included in an emission layer of the organic light-emitting device. In one or more embodiments, the organic layer may include, as the organometallic compound, Compound 1 and Compound 2. In this regard, Compound 1 and Compound 2 may be included in an identical layer (for example, Compound 1 and Compound 2 all may be included in an emission layer).

The first electrode may be an anode, which is a hole injection electrode, and the second electrode may be a cathode, which is an electron injection electrode; or the first electrode may be a cathode, which is an electron injection electrode, and the second electrode may be an anode, which is a hole injection electrode.

In one or more embodiments, in the organic light-emitting device, the first electrode may be an anode, and the second electrode may be a cathode, and the organic layer further includes a hole transport region disposed between the first electrode and the emission layer and an electron transport region disposed between the emission layer and the second electrode, wherein the hole transport region may include a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, and wherein the electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

The term “organic layer” as used herein refers to a single layer and/or a plurality of layers disposed between the first electrode and the second electrode of the organic light-emitting device. The “organic layer” may include, in addition to an organic compound, an organometallic complex including metal.

FIG. 1 is a schematic view of an organic light-emitting device 10 according to an embodiment. Hereinafter, the structure of an organic light-emitting device according to an embodiment and a method of manufacturing an organic light-emitting device according to an embodiment will be described in connection with FIG. 1. The organic light-emitting device 10 includes a first electrode 11, an organic layer 15, and a second electrode 19, which are sequentially stacked in this stated order.

A substrate may be additionally disposed under the first electrode 11 or above the second electrode 19. For use as the substrate, any substrate used in general organic light-emitting devices may be used, and the substrate may be a glass substrate or a transparent plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance.

The first electrode 11 may be formed by depositing or sputtering a material for forming the first electrode 11 on the substrate. The first electrode 11 may be an anode. The material for forming the first electrode 11 may be selected from materials with a high work function to facilitate hole injection. The first electrode 11 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. The material for forming the first electrode may be, for example, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO₂), and zinc oxide (ZnO). In one or more embodiments, magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) may be used as the material for forming the first electrode.

The first electrode 11 may have a single-layered structure or a multi-layered structure including two or more layers. For example, the first electrode 11 may have a three-layered structure of ITO/Ag/ITO, but the structure of the first electrode 110 is not limited thereto.

The organic layer 15 is disposed on the first electrode 11.

The organic layer 15 may include a hole transport region, an emission layer, and an electron transport region.

The hole transport region may be disposed between the first electrode 11 and the emission layer.

The hole transport region may include a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer, or any combination thereof.

The hole transport region may include only either a hole injection layer or a hole transport layer. In one or more embodiments, the hole transport region may have a hole injection layer/hole transport layer structure or a hole injection layer/hole transport layer/electron blocking layer structure, which are sequentially stacked in this stated order from the first electrode 11.

A hole injection layer may be formed on the first electrode 11 by using one or more suitable methods selected from vacuum deposition, spin coating, casting, or Langmuir-Blodgett (LB) deposition.

When a hole injection layer is formed by vacuum deposition, the deposition conditions may vary depending on a material used to form the hole injection layer, and the structure and thermal characteristics of the hole injection layer. For example, the deposition conditions may include a deposition temperature of about 100° C. to about 500° C., a vacuum pressure of about 10⁻⁸ torr to about 10⁻³ torr, and a deposition rate of about 0.01 Angstroms per second (Å/sec) to about 100 Å/sec. However, the deposition conditions are not limited thereto.

When the hole injection layer is formed using spin coating, coating conditions may vary depending on the material used to form the hole injection layer, and the structure and thermal properties of the hole injection layer. For example, a coating speed may be from about 2,000 revolutions per minute (rpm) to about 5,000 rpm, and a temperature at which a heat treatment is performed to remove a solvent after coating may be from about 80° C. to about 200° C. However, the coating conditions are not limited thereto.

Conditions for forming a hole transport layer and an electron blocking layer may be understood by referring to conditions for forming the hole injection layer.

The hole transport region may include at least one selected from m-MTDATA, TDATA, 2-TNATA, NPB, β-NPB, TPD, Spiro-TPD, Spiro-NPB, methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzene sulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrene sulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrene sulfonate) (PANI/PSS), a compound represented by Formula 201 below, and a compound represented by Formula 202 below:

Ar₁₀₁ and Ar₁₀₂ in Formula 201 may each independently be selected from:

a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an acenaphthylene group, a fluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, and a pentacenylene group; and

a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an acenaphthylene group, a fluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, and a pentacenylene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.

xa and xb in Formula 201 may each independently be an integer from 0 to 5, or 0, 1, or 2. For example, xa may be 1 and xb may be 0, but xa and xb are not limited thereto.

R₁₀₁ to R₁₀₈, R₁₁₁ to R₁₁₉, and R₁₂₁ to R₁₂₄ in Formulae 201 and 202 may each independently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, pentyl group, a hexyl group, or the like), and a C₁-C₁₀ alkoxy group (for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, or the like);

a C₁-C₁₀ alkyl group and a C₁-C₁₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof;

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenyl group, and a pyrenyl group; and

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenyl group, and a pyrenyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, and a C₁-C₁₀ alkoxy group, but embodiments of the present disclosure are not limited thereto.

R₁₀₉ in Formula 201 may be selected from:

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinyl group; and

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinyl group.

In one or more embodiments, the compound represented by Formula 201 may be represented by Formula 201A, but embodiments of the present disclosure are not limited thereto:

R₁₀₁, R₁₁₁, R₁₁₂, and R₁₀₉ in Formula 201A may be understood by referring to the description provided herein.

For example, the compound represented by Formula 201 and the compound represented by Formula 202 may include compounds HT1 to HT20 illustrated below, but are not limited thereto.

A thickness of the hole transport region may be in a range of about 100 Angstroms (Å) to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When the hole transport region includes at least one of a hole injection layer and a hole transport layer, the thickness of the hole injection layer may be in a range of about 100 Å to about 10,000 Å, and for example, about 100 Å to about 1,000 Å, and the thickness of the hole transport layer may be in a range of about 50 Å to about 2,000 Å, and for example, about 100 Å to about 1500 Å. While not wishing to be bound by theory, it is understood that when the thicknesses of the hole transport region, the hole injection layer, and the hole transport layer are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The hole transport region may further include, in addition to these materials, a charge-generation material for the improvement of conductive properties. The charge-generation material may be homogeneously or non-homogeneously dispersed in the hole transport region.

The charge-generation material may be, for example, a p-dopant. The p-dopant may be one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but embodiments of the present disclosure are not limited thereto. Non-limiting examples of the p-dopant are a quinone derivative, such as tetracyanoquinonedimethane (TCNQ) or 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane (F4-TCNQ); a metal oxide, such as a tungsten oxide or a molybdenium oxide; and a cyano group-containing compound, such as Compound HT-D1 below, but are not limited thereto.

The hole transport region may include a buffer layer.

Also, the buffer layer may compensate for an optical resonance distance according to a wavelength of light emitted from the emission layer, and thus, efficiency of a formed organic light-emitting device may be improved.

Then, an emission layer (EML) may be formed on the hole transport region by vacuum deposition, spin coating, casting, LB deposition, or the like. When the emission layer is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to those applied to form the hole injection layer although the deposition or coating conditions may vary according to the material used to form the emission layer.

Meanwhile, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be selected from materials for the hole transport region described above and materials for a host to be explained later. However, the material for the electron blocking layer is not limited thereto. For example, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be mCP, which will be explained further later.

The emission layer may include a host and a dopant, and the dopant may include the organometallic compound represented by Formula 1.

The host may include at least one selected from TPBi, TBADN, ADN (also referred to as “DNA”), CBP, CDBP, TCP, mCP, Compound H50, and Compound H51:

In one or more embodiments, the host may further include a compound represented by Formula 301 below:

Ar₁₁₁ and Ar₁₁₂ in Formula 301 may each independently be selected from:

a phenylene group, a naphthylene group, a phenanthrenylene group, and a pyrenylene group; and

a phenylene group, a naphthylene group, a phenanthrenylene group, and a pyrenylene group, each substituted with at least one selected from a phenyl group, a naphthyl group, and an anthracenyl group.

Ar₁₁₃ to Ar₁₁₆ in Formula 301 may each independently be selected from:

a C₁-C₁₀ alkyl group, a phenyl group, a naphthyl group, a phenanthrenyl group, and a pyrenyl group; and

a phenyl group, a naphthyl group, a phenanthrenyl group, and a pyrenyl group, each substituted with at least one selected from a phenyl group, a naphthyl group, and an anthracenyl group.

g, h, i, and j in Formula 301 may each independently be an integer selected from 0 to 4, and may be, for example, 0, 1, or 2.

Ar₁₁₃ to Ar₁₁₆ in Formula 301 may each independently be selected from:

a C₁-C₁₀ alkyl group substituted with at least one selected from a phenyl group, a naphthyl group, and an anthracenyl group;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl, a phenanthrenyl group, and a fluorenyl group;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, and a fluorenyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, and a fluorenyl group; and

but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, the host may include a compound represented by Formula 302 below:

Ar₁₂₂ to Ar₁₂₅ in Formula 302 are the same as described in detail in connection with Ar₁₁₃ in Formula 301.

Ar₁₂₆ and Ar₁₂₇ in Formula 302 may each independently be a C₁-C₁₀ alkyl group (for example, a methyl group, an ethyl group, or a propyl group).

k and l in Formula 302 may each independently be an integer selected from 0 to 4. For example, k and l may be 0, 1, or 2.

The compound represented by Formula 301 and the compound represented by Formula 302 may include Compounds H1 to H42 illustrated below, but are not limited thereto.

When the organic light-emitting device is a full color organic light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, and a blue emission layer. In one or more embodiments, due to a stack structure including a red emission layer, a green emission layer, and/or a blue emission layer, the emission layer may emit white light.

When the emission layer includes a host and a dopant, an amount of the dopant may be in a range of about 0.01 parts to about 15 parts by weight based on 100 parts by weight of the host, but is not limited thereto.

A thickness of the emission layer may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. While not wishing to be bound by theory, it is understood that when the thickness of the emission layer is within this range, excellent light emission characteristics may be obtained without a substantial increase in driving voltage.

Then, an electron transport region may be disposed on the emission layer.

The electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

For example, the electron transport region may have a hole blocking layer/electron transport layer/electron injection layer structure or an electron transport layer/electron injection layer structure, but the structure of the electron transport region is not limited thereto. The electron transport layer may have a single-layered structure or a multi-layered structure including two or more different materials.

Conditions for forming the hole blocking layer, the electron transport layer, and the electron injection layer which constitute the electron transport region may be understood by referring to the conditions for forming the hole injection layer.

When the electron transport region includes a hole blocking layer, the hole blocking layer may include, for example, at least one of BCP, Bphen, and BAlq but is not limited thereto.

A thickness of the hole blocking layer may be in a range of about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å. While not wishing to be bound by theory, it is understood that when the thickness of the hole blocking layer is within these ranges, the hole blocking layer may have an improved hole blocking ability without a substantial increase in driving voltage.

The electron transport layer may further include at least one selected from BCP, Bphen, Alq₃, BAlq, TAZ, and NTAZ.

In one or more embodiments, the electron transport layer may include at least one of ET1 and ET2, but are not limited thereto:

A thickness of the electron transport layer may be in a range of about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. While not wishing to be bound by theory, it is understood that when the thickness of the electron transport layer is within the range described above, the electron transport layer may have satisfactory electron transport characteristics without a substantial increase in driving voltage.

Also, the electron transport layer may further include, in addition to the materials described above, a metal-containing material.

The metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (LiQ) or ET-D2.

The electron transport region may include an electron injection layer (EIL) that promotes flow of electrons from the second electrode 19 thereinto.

The electron injection layer may include at least one selected from LiF, NaCl, CsF, Li₂O, and BaO.

A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å. While not wishing to be bound by theory, it is understood that when the thickness of the electron injection layer is within the range described above, the electron injection layer may have satisfactory electron injection characteristics without a substantial increase in driving voltage.

The second electrode 19 is disposed on the organic layer 15. The second electrode 19 may be a cathode. A material for forming the second electrode 19 may be selected from metal, an alloy, an electrically conductive compound, and a combination thereof, which have a relatively low work function. For example, lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) may be used as a material for forming the second electrode 19. In one or more embodiments, to manufacture a top-emission type light-emitting device, a transmissive electrode formed using ITO or IZO may be used as the second electrode 19.

Hereinbefore, the organic light-emitting device has been described with reference to FIG. 1, but is not limited thereto.

Another aspect of the present disclosure provides a diagnostic composition including at least one organometallic compound represented by Formula 1.

The organometallic compound represented by Formula 1 provides high photoluminescent efficiency. Accordingly, a diagnostic composition including the organometallic compound may have high diagnosis efficiency.

The diagnostic composition may be used in various applications including a diagnosis kit, a diagnosis reagent, a bio-sensor, or a bio-marker.

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear or branched saturated aliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms, and non-limiting examples thereof include a methyl group, an ethyl group, a propyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group. The term “C₁-C₆₀ alkylene group” as used herein refers to a divalent group having the same structure as the C₁-C₆₀ alkyl group.

The term “C₁-C₆₀ alkoxy group” as used herein refers to a monovalent group represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group), and non-limiting examples thereof include a methoxy group, an ethoxy group, and an iso-propyloxy (iso-propoxy) group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a hydrocarbon group formed by including at least one carbon-carbon double bond in the middle or at the terminus of the C₂-C₆₀ alkyl group, and examples thereof include an ethenyl group, a propenyl group, and a butenyl group. The term “C₂-C₆₀ alkenylene group” as used herein refers to a divalent group having the same structure as the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a hydrocarbon group formed by including at least one carbon-carbon triple bond in the middle or at the terminus of the C₂-C₆₀ alkyl group, and examples thereof include an ethynyl group, and a propynyl group. The term “C₂-C₆₀ alkynylene group” as used herein refers to a divalent group having the same structure as the C₂-C₆₀ alkynyl group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, and non-limiting examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term “C₃-C₁₀ cycloalkylene group” as used herein refers to a divalent group having the same structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein refers to a monovalent saturated monocyclic group having at least one heteroatom selected from N, O, P, Si and S as a ring-forming atom and 1 to 10 carbon atoms, and non-limiting examples thereof include a tetrahydrofuranyl group and a tetrahydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkylene group” as used herein refers to a divalent group having the same structure as the C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group” as used herein refers to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one carbon-carbon double bond in the ring thereof and which is not aromatic, and non-limiting examples thereof include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀ cycloalkenylene group” as used herein refers to a divalent group having the same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein refers to a monovalent monocyclic group that has at least one heteroatom selected from N, O, P, Si, and S as a ring-forming atom, 1 to 10 carbon atoms, and at least one carbon-carbon double bond in its ring. Examples of the C₁-C₁₀ heterocycloalkenyl group are a 2,3-dihydrofuranyl group and a 2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylene group” as used herein refers to a divalent group having the same structure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and the term “C₆-C₆₀ arylene group” as used herein refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Non-limiting examples of the C₆-C₆₀ aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylene group each include two or more rings, the rings may be fused to each other.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalent group having a heterocyclic aromatic system that has at least one heteroatom selected from N, O, P, Si, and S as a ring-forming atom, and 1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group,” as used herein refers to a divalent group having a heterocyclic aromatic system that has at least one heteroatom selected from N, O, P, Si, and S as a ring-forming atom, and 1 to 60 carbon atoms. Non-limiting examples of the C₁-C₆₀ heteroaryl group include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group. When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group each include two or more rings, the rings may be fused to each other.

The term “C₆-C₆₀ aryloxy group” as used herein indicates —OA₁₀₂ (wherein A₁₀₂ is the C₆-C₆₀ aryl group), and a C₆-C₆₀ arylthio group used herein indicates —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group).

A monovalent non-aromatic condensed polycyclic group as used herein refers to a monovalent group (for example, having 8 to 60 carbon atoms) that has two or more rings condensed to each other, only carbon atoms as a ring-forming atom, and which is non-aromatic in the entire molecular structure. Examples of the monovalent non-aromatic condensed polycyclic group include a fluorenyl group. The term “divalent non-aromatic condensed polycyclic group,” as used herein, refers to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group (for example, having 2 to 60 carbon atoms) that has two or more rings condensed to each other, has a heteroatom selected from N, O, P, Si, and S, other than carbon atoms, as a ring-forming atom, and which is non-aromatic in the entire molecular structure. Non-limiting examples of the monovalent non-aromatic condensed heteropolycyclic group include a carbazolyl group. The term “divalent non-aromatic condensed heteropolycyclic group,” as used herein, refers to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

The term “C₅-C₃₀ carbocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, 5 to 30 carbon atoms only. The C₅-C₃₀ carbocyclic group may be a monocyclic group or a polycyclic group.

The term “C₁-C₃₀ heterocyclic group” as used herein refers to a saturated or unsaturated cyclic group having at least one heteroatom selected from N, O, P, Si, and S, other than 1 to 30 carbon atoms, as a ring-forming atom. The C₁-C₃₀ heterocyclic group may be a monocyclic group or a polycyclic group.

At least one of substituents of the substituted C₅-C₃₀ carbocyclic group, substituted C₂-C₃₀ heterocyclic group, substituted C₁-C₆₀ alkyl group, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynyl group, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkyl group, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀ cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group, substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group, substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉); and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉),

wherein Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with at least one selected from a C₁-C₆₀ alkyl group and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.

When a group containing a specified number of carbon atoms is substituted with any of the groups listed in the preceding paragraph, the number of carbon atoms in the resulting “substituted” group is defined as the sum of the carbon atoms contained in the original (unsubstituted) group and the carbon atoms (if any) contained in the substituent. For example, when the term “substituted C₁-C₃₀ alkyl” refers to a C₁-C₃₀ alkyl group substituted with C₆-C₃₀ aryl group, the total number of carbon atoms in the resulting aryl substituted alkyl group is C₇-C₆₀.

Hereinafter, a compound and an organic light-emitting device according to embodiments of the present disclosure are described in detail with reference to Synthesis Examples and Examples. However, the organic light-emitting device is not limited thereto. The wording “B was used instead of A” used in describing Synthesis Examples means that an amount of A used was identical to an amount of B used, in terms of a molar equivalent.

EXAMPLES Synthesis Example 1

Synthesis of Intermediate L1

70 milliliters (ml) of tetrahydrofuran (THF) and 20 ml of distilled water were mixed with 4.93 grams (g) (18.53 millimoles, mmol) of 2,6-dichloro-4-mesitylpyridine, 2.05 g (14.82 mmol) of 2-hydroxyphenyl)boronic acid, 0.89 g (0.93 mmol) of Pd(PPh)₃, and 15.36 g (55.59 mmol) of K₂CO₃, and the mixture was refluxed and stirred for 6 hours. The mixture was cooled to room temperature, and an organic layer was extracted therefrom by using ethyl acetate (EA). The organic layer was dried by using anhydrous magnesium sulfate (MgSO₄), and a filtrate was obtained by filtering the organic layer under reduced pressure. The residue obtained therefrom was purified by column chromatography using EA:hexane=1:50 as an eluent, thereby completing the preparation of 3.9 g (65%) of Intermediate L1.

LC-MS m/z=324.15 (M+H⁺)

Synthesis of Intermediate L2

20 ml of THF and 5 ml of distilled water were mixed with 2.43 g (7.52 mmol) of Intermediate L1, 3.35 g (9.02 mmol) of 2-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)dibenzo[b,d]furan-4-yl)pyridine, 0.43 g (0.38 mmol) of Pd(PPh)₃, 3.12 g (22.55 mmol) of K₂CO₃, and 0.39 g (2.25 mmol) of Ba(OH)₂), and the mixture was refluxed and stirred for 6 hours. The mixture was cooled to room temperature, and an organic layer was extracted therefrom by using ethyl acetate (EA). The organic layer was dried by using anhydrous magnesium sulfate (MgSO₄), and a filtrate was obtained by filtering the organic layer under reduced pressure. The residue obtained therefrom was purified by column chromatography using EA:hexane=1:10 as an eluent, thereby completing the preparation of 2.00 g (50%) of Intermediate L2.

LC-MS m/z=533.29 (M+H⁺)

Synthesis of Compound 1

35 ml of benzonitrile was mixed with 1.91 g (3.58 mmol) of Intermediate L2 and 1.52 g (3.22 mmol) of PtCl₂(NCPh)₂. The reaction solution was stirred at a temperature of 140° C. for 6 hours and was then cooled. The reaction solution was distilled to remove benzonitrile, and an organic layer was extracted therefrom by using methylene chloride (MC). The organic layer was dried by using anhydrous magnesium sulfate (MgSO₄), and a filtrate was obtained by filtering the organic layer under reduced pressure. The residue obtained therefrom was purified through column chromatography using EA:MC:hexane=2:2:8 as an eluent, thereby completing the preparation of 1.30 g (50%) of Compound 1.

LC-MS m/z=726.19 (M+H⁺)

Synthesis Example 2

Synthesis of Intermediate L3

7 ml of THF and 2 ml of distilled water were mixed with 0.96 g (2.97 mmol) of Intermediate L1, 1.53 g (3.56 mmol) of 4-(naphthalen-1-yl(pyridin-2-yl)amino)dibenzo[b,d]furan-2-yl)boronic acid, 0.17 g (0.15 mmol) of Pd(PPh)₃, 1.23 g (8.9 mmol) of K₂CO₃, and 0.15 g (0.89 mmol) of Ba(OH)₂, and the mixture was refluxed and stirred for 6 hours. The mixture was cooled to room temperature, and an organic layer was extracted therefrom by using ethyl acetate (EA). The organic layer was dried by using anhydrous magnesium sulfate (MgSO₄), and a filtrate was obtained by filtering the organic layer under reduced pressure. The residue obtained therefrom was purified through column chromatography using EA:hexane=1:10 as an eluent, thereby completing the preparation of 0.8 g (40%) of Intermediate L3.

LC-MS m/z=674.26 (M+H+)

Synthesis of Compound 2

10 ml of benzonitrile was mixed with 0.8 g (1.19 mmol) of Intermediate L3 and 0.59 g (1.25 mmol) of PtCl₂(NCPh)₂. The reaction solution was stirred at a temperature of 140° C. for 6 hours, and was then cooled. The reaction solution was distilled to remove benzonitrile, and an organic layer was extracted therefrom by using methylene chloride (MC). The organic layer was dried by using anhydrous magnesium sulfate (MgSO₄), and a filtrate was obtained by filtering the organic layer under reduced pressure. The residue obtained therefrom was purified through column chromatography using EA:MC:hexane=1:1:8 as an eluent, thereby completing the preparation of 0.55 g (53%) of Compound 2.

LC-MS m/z=867.17 (M+H+)

Evaluation Example 1: Photoluminescent Spectrum Evaluation

A photoluminescent (PL) spectrum, a HOMO energy level, and a LUMO energy level of Compounds 1 and 2 were evaluated according to a method shown in Table 2. The PL spectra of Compounds 1 and 2 are respectively shown in FIGS. 2 and 3, and a maximum photoluminescent wavelength, a full width at half maximum (FWHM), a full width at quarter maximum (FWQM), a LUMO energy level, and a HOMO energy level of Compounds 1 and 2 are shown in Table 3.

TABLE 2 Photo- Each of Compounds 1 and 2 was diluted to a concentration luminescent of 10 millimolar (mM) with toluene, and the PL spectrum (PL) was measured by using an ISC PC1 spectrofluorometer spectrum equipped with a xenon lamp (@ 298 Kelvins, K). HOMO A voltage (V)-current (A) graph of each of Compounds 1 energy level and 2 was obtained by using a cyclic voltammetry (CV) evaluation (electrolyte: 0.1 molar (M) Bu₄NPF₆/solvent: CH₂Cl₂/ method electrode: 3 electrode system (working electrode: Pt disc (1 mm diameter), reference electrode: Pt wire, and auxiliary electrode: Pt wire)), and the HOMO energy level of each of Compounds 1 and 2 was calculated from an oxidation onset of the V-A graph. LUMO Each of Compounds 1 and 2 was diluted to a concentration energy level of 1 × 10⁻⁵ M with CHCl₃, a UV absorption spectrum evaluation was measured at room temperature by using a Shimadzu method UV-350 spectrometer, and an optical band gap (Eg) was obtained from an edge of the UV absorption spectrum. The LUMO energy level was calculated by using the Eg and the HOMO energy level.

TABLE 3 Compound 1 Compound 2 λ_(max) 532 nm 521 nm FWHM 58 nm 50 nm FWQM 83 nm 82 nm HOMO −5.092 eV −5.226 eV LUMO −2.515 eV −2.593 eV (nm = nanometers, eV = electron volts)

Referring to FIG. 3, it was determined that Compounds 1 and 2 had a relatively small FWHM and electrical characteristics suitable for use in an organic light-emitting device.

Example 1

An anode was prepared by cutting an ITO glass substrate to a size of 50 mm×50 mm×0.5 mm (mm=millimeters), ultrasonically cleaning the ITO glass substrate by using acetone, iso-propyl alcohol, and pure water each for 15 minutes, and exposing the ITO glass substrate to UV irradiation for 30 minutes and ozone to clean the ITO glass substrate.

m-MTDATA was deposited on the ITO glass substrate (anode) at a deposition rate of 1 Angstroms per second (Å/sec) to form a hole injection layer having a thickness of 600 Angstroms (Å), and α-NPD was deposited on the hole injection layer at a deposition rate of 1 Å/sec to form a hole transport layer having a thickness of 250 Å.

Compound 1 (dopant) and Compound CBP (host) were respectively co-deposited on the hole transport layer at deposition rates of 0.1 Å/sec and 1 Å/sec to form an emission layer having a thickness of 400 Å.

BAlq was deposited on the emission layer at a deposition rate of 1 Å/sec to form a hole blocking layer having a thickness of 50 Å, Alq₃ was deposited on the hole blocking layer to form an electron transport layer having a thickness of 300 Å, LiF was deposited on the electron transport layer to form an electron injection layer having a thickness of 10 Å, and Al was vacuum-deposited on the electron injection layer to form a second electrode (cathode) having a thickness of 1,200 Å, thereby completing the manufacture of an organic light-emitting device having an ITO/m-MTDATA (600 Å)/α-NPD (250 Å)/CBP+10% (Compound 1) (400 Å)/BAlq (50 Å)/Alq₃ (300 Å)/LiF (10 Å)/Al (1,200 Å) structure.

Example 2 and Comparative Examples A and B

Organic light-emitting devices were manufactured in the same manner as in Example 1, except that Compounds shown in Table 4 were each used instead of Compound 1 as a dopant in forming an emission layer.

Evaluation Example 2: Evaluation of Characteristics of Organic Light-Emitting Devices

The driving voltage, emission efficiency, power efficiency, color purity, and quantum emission efficiency of the organic light-emitting devices manufactured according to Examples 1 and 2 and Comparative Examples A and B were evaluated. Results thereof are shown in Table 4. This evaluation was performed by using a current-voltage meter (Keithley 2400) and a luminance meter (Minolta Cs-1,000A).

TABLE 4 Quantum Driving Emission Power emission voltage efficiency efficiency efficiency Dopant (V) (cd/A) (lm/W) ClEx ClEy (%) Example 1 Compound 5.1 50.2 34.2 0.414 0.570 14 1 Example 2 Compound 4.9 69.4 44.0 0.336 0.616 18 2 Comparative Compound 5.4 50.8 31.6 0.416 0.542 13 Example A A Comparative Compound 6.2 19.1 9.9 0.321 0.604 6 Example B B (V = volts, cd/A = candelas per ampere, lm/W = lumens per watt)

Referring to Table 4, it was determined that, compared to those values of the organic light-emitting device of Comparative Example B, the organic light-emitting device of Example 1 had a low driving voltage, high emission efficiency, high power efficiency, and high quantum emission efficiency, and compared to those values of the organic light-emitting device of Comparative Example A, the organic light-emitting device of Example 2 had a low driving voltage, high emission efficiency, high power efficiency, and high quantum emission efficiency.

The organometallic compound according to one or more embodiments has excellent electrical characteristics and thermal stability. Accordingly, an organic light-emitting device including the organometallic compound may have excellent driving voltage, photoluminescent efficiency, power efficiency, color purity, and lifespan characteristics. In addition, since the organometallic compound has excellent phosphorescent photoluminescent characteristics, a diagnostic composition having high diagnosis efficiency may be provided by using the organometallic compound.

It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.

While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the following claims. 

What is claimed is:
 1. An organometallic compound represented by Formula 1:

wherein, in Formula 1, M is beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt), or gold (Au), X₁ is O or S, and a bond between X₁ and M is a covalent bond, i) X₂ and X₄ are each N, each of a bond between X₂ and M and a bond between X₄ and M is a coordinate bond, X₃ is C, and a bond between X₃ and M is a covalent bond; ii) X₂ and X₃ are each N, each of a bond between X₂ and M and a bond between X₃ and M is a coordinate bond, X₄ is C, and a bond between X₄ and M is a covalent bond; or iii) X₃ and X₄ are each N, each of a bond between X₃ and M and a bond between X₄ and M is a coordinate bond, X₂ is C, and a bond between X₂ and M is a covalent bond, Y₁ to Y₇ are each independently C or N, Y₈ and Y₉ are each independently C, N, O, or S, a bond between Y₁ and Y₈, a bond between Y₁ and Y₂, a bond between X₂ and Y₃, a bond between X₂ and Y₄, a bond between X₃ and Y₅, a bond between X₃ and Y₆, a bond between X₄ and Y₇, and a bond between X₄ and Y₉ are each independently a single bond or a double bond, CY₁, CY₂, and CY₄ are each independently selected from a C₅-C₃₀ carbocyclic group and a C₁-C₃₀ heterocyclic group, provided that CY₂ is not an azadibenzofuran group, an azadibenzothiophene group, an azadibenzoselenophene group, an azacarbazole group, an azafluorene group, and an azadibenzosilole group, which each include at least one N as a ring-forming atom, CY₃ is selected from: a dibenzofuran group, a dibenzothiophene group, a dibenzoselenophene group, a carbazole group, a fluorene group, and a dibenzosilole group; and an azadibenzofuran group, an azadibenzothiophene group, an azadibenzoselenophene group, an azacarbazole group, an azafluorene group, and an azadibenzosilole group, which each include at least one N as a ring-forming atom, T₁ to T₃ are each independently selected from *—O—*′, *—S—*′, *—C(R₅)(R₆)—*′, *—C(R₅)═*′, *═C(R₅)—*′, *—C(R₅)═C(R₆)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—Si(R₅)(R₆)—*′, *—Ge(R₅)(R₆)—*′, *—B(R₅)—*′, *—N(R₅)—*′, and *—P(R₅)—*′, R₅ and R₆ are optionally linked to each other via a first linking group to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, b1 to b3 are each independently 0, 1, 2, or 3, wherein when b1 is zero, *-(T₁)_(b1)-*′ is a single bond, when b2 is zero, *-(T₂)_(b2)-*′ is a single bond, and when b3 is zero, *-(T₃)_(b3)-*′ is a single bond, R₁ to R₆ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₆₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), —P(═O)(Q₈)(Q₉), and —P(Q₈)(Q₉), a1 to a4 are each independently 0, 1, 2, 3, 4, or 5, two of groups R₁ in the number of a1 are optionally linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two of groups R₂ in the number of a2 are optionally linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two of groups R₃ in the number of a3 are optionally linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two of groups R₄ in the number of a4 are optionally linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two or more neighboring groups selected from R₁ to R₄ are optionally linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, one of R₅ and R₆ are optionally linked to R₃ to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, one of R₅ and R₆ are optionally linked to R₄ to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, and at least one substituent selected from a substituent(s) of the substituted C₅-C₃₀ carbocyclic group, the substituted C₁-C₃₀ heterocyclic group, the substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —Ge(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), —P(═O)(Q₁₈)(Q₁₉), and —P(Q₁₈)(Q₁₉); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —Ge(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), —P(═O)(Q₂₈)(Q₂₉), and —P(Q₂₈)(Q₂₉); and —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —Ge(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), P(═O)(Q₃₈)(Q₃₉), and —P(Q₃₈)(Q₃₉), wherein Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with at least one of a C₁-C₆₀ alkyl group and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.
 2. The organometallic compound of claim 1, wherein CY₁ and CY₄ are each independently selected from a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a 1,2,3,4-tetrahydronaphthalene group, a furan group, a thiophene group, a selenophene group, a pyrrole group, a cyclopentadiene group, a silole group, a benzofuran group, a benzothiophene group, a benzoselenophene group, an indole group, an indene group, a benzosilole group, a dibenzofuran group, a dibenzothiophene group, a dibenzoselenophene group, a carbazole group, a fluorene group, a dibenzosilole group, an azadibenzofuran group, an azadibenzothiophene group, an azadibenzoselenophene group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a phenanthroline group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzoxadiazole group, a benzothiadiazole group, a 5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinoline group, and CY₂ is selected from a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a 1,2,3,4-tetrahydronaphthalene group, a furan group, a thiophene group, a selenophene group, a pyrrole group, a cyclopentadiene group, a silole group, a benzofuran group, a benzothiophene group, a benzoselenophene group, an indole group, an indene group, a benzosilole group, a dibenzofuran group, a dibenzothiophene group, a dibenzoselenophene group, a carbazole group, a fluorene group, a dibenzosilole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a phenanthroline group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzoxadiazole group, a benzothiadiazole group, a 5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinoline group.
 3. The organometallic compound of claim 1, wherein T₁ to T₃ are each independently selected from *—O—*′, *—S—*′, *—C(R₅)(R₆)—*′, *—Si(R₅)(R₆)—*′, *—N(R₅)—*′, and *—P(R₅)—*′.
 4. The organometallic compound of claim 1, wherein T₁ to T₃ are each independently selected from *—C(R₅)(R₆)—*′, *—Si(R₅)(R₆)—*′, and *—Ge(R₅)(R₆)—*′, R₅ and R₆ are linked to each other via a first linking group, the first linking group is selected from a single bond, *—O—*′, *—S—*′, *—C(R₉)(R₁₀)—*′ *—C(R₉)═*′, *═C(R₉)—*′, *—C(R₉)═C(R₁₀)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—Si(R₉)(R₁₀)—*′, *—Ge(R₉)(R₁₀)—*′, *—B(R₉)—*′, *—N(R₉)—*′, and *—P(R₉)—*′, R₉ and R₁₀ are each independently the same as described in connection with R₅ in claim 1, and * and *′ each indicate a binding site to a neighboring atom.
 5. The organometallic compound of claim 1, wherein b1, b2, and b3 are each zero; b1 is one, and b2 and b3 are each zero; b2 is one, and b1 and b3 are each zero; or b3 is one, and b1 and b2 are each zero.
 6. The organometallic compound of claim 1, wherein R₁ to R₆ are each independently selected from: hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, —SF₅, C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, and a pyrimidinyl group; a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group; a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅); and —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), —P(═O)(Q₈)(Q₉), and —P(Q₈)(Q₉), wherein Q₁ to Q₉ and Q₃₃ to Q₃₅ are each independently selected from: —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and —CD₂CDH₂; an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group; and an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group, each substituted with at least one selected from deuterium, a C₁-C₁₀ alkyl group, and a phenyl group.
 7. The organometallic compound of claim 1, wherein R₁ to R₆ are each independently selected from: hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, an iso-hexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an iso-heptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an iso-octyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an iso-nonyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an iso-decyl group, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group; a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, an iso-hexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an iso-heptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an iso-octyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an iso-nonyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an iso-decyl group, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group, each substituted with at least one selected from deuterium, —F, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a cyano group, a nitro group, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group; and —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉), wherein Q₁ to Q₉ are each independently selected from: —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and —CD₂CDH₂; an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group; and an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group, each substituted with at least one selected from deuterium, a C₁-C₁₀ alkyl group, and a phenyl group.
 8. The organometallic compound of claim 1, wherein R₁ to R₆ are each independently selected from hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, groups represented by Formulae 9-1 to 9-19, groups represented by Formulae 10-1 to 10-46, and —Si(Q₃)(Q₄)(Q₅):

wherein * in Formulae 9-1 to 9-19 and 10-1 to 10-46 indicates a binding site to a neighboring atom.
 9. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is selected from groups represented by Formulae CY1-1 to CY1-16:

wherein, in Formulae CY1-1 to CY1-16, X₁₁ is N or C(R₁₁), X₁₂ is N or C(R₁₂), X₁₃ is N or C(R₁₃), X₁₄ is N or C(R₁₄), X₁₅ is N or C(R₁₅), X₁₆ is N or C(R₁₆), X₁₇ is N or C(R₁₇), and X₁₈ is N or C(R₁₈), X₁₉ is C(R_(19a))(R_(19b)), N(R₁₉), O, S, Se, or Si(R_(19a))(R_(19b)), R₁₁ to R₁₉ and R_(19a) to R_(19c) are each independently the same as described in connection with R₁ in claim 1, and * and *′ each indicate a binding site to a neighboring atom.
 10. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is selected from groups represented by Formulae CY2-1 to CY2-11:

wherein, in Formulae CY2-1 to CY2-11, X₂₁ is N or C(R₂₁), X₂₂ is N or C(R₂₂), X₂₃ is N or C(R₂₃), X₂₄ is N or C(R₂₄), X₂₅ is N or C(R₂₅), X₂₆ is N or C(R₂₆), and X₂₇ is N or C(R₂₇), X₂₉ is C(R_(29a))(R_(29b)), N(R₂₉), O, S, Se, or Si(R_(29a))(R_(29b)), R₂₁ to R₂₉, R_(29a), and R_(29b) are each independently the same as described in connection with R₂ in claim 1, and *, *′, and *″ each indicate a binding site to a neighboring atom.
 11. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is selected from groups represented by Formulae CY3-1 to CY3-8:

wherein, in Formulae CY3-1 to CY3-8, X₃₁ is N or C(R₃₁), X₃₃ is N or C(R₃₃), X₃₄ is N or C(R₃₄), X₃₅ is N or C(R₃₅), X₃₆ is N or C(R₃₆), and X₃₇ is N or C(R₃₇), X₃₉ is C(R_(39a))(R_(39b)), N(R₃₉), O, S, Se, or Si(R_(39a))(R_(39b)), R₃₁, R₃₃ to R₃₇, R₃₉, R_(39a), and R_(39b) are each independently the same as described in connection with R₃ in claim 1, and *, *′, and *″ each indicate a binding site to a neighboring atom.
 12. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is selected from groups represented by Formulae CY4-1 to CY4-8:

wherein, in Formulae CY4-1 to CY4-8, X₄₁ is N or C(R₄₁), X₄₂ is N or C(R₄₂), X₄₃ is N or C(R₄₃), X₄₄ is N or C(R₄₄), X₄₅ is N or C(R₄₅), X₄₆ is N or C(R₄₆), X₄₇ is N or C(R₄₇), and X₄₈ is N or C(R₄₈), R₄₁ to R₄₈ are each independently the same as described in connection with R₄ in claim 1, and * and *′ each indicate a binding site to a neighboring atom.
 13. The organometallic compound of claim 1, wherein the organometallic compound is represented by one selected from Formulae 1-1 to 1-4:

wherein, in Formulae 1-1 to 1-4, M, X₁, T₁ to T₃, and b1 to b3 are each independently the same as described in claim 1, X₁₁ is N or C(R₁₁), X₁₂ is N or C(R₁₂), X₁₃ is N or C(R₁₃), and X₁₄ is N or C(R₁₄), X₂₁ is N or C(R₂₁), X₂₂ is N or C(R₂₂), and X₂₃ is N or C(R₂₃), X₃₁ is N or C(R₃₁), X₃₃ is N or C(R₃₃), X₃₄ is N or C(R₃₄), X₃₅ is N or C(R₃₅), X₃₆ is N or C(R₃₆), and X₃₇ is N or C(R₃₇), X₃₉ is C(R_(39a))(R_(39b)), N(R₃₉), O, S, Se, or Si(R_(39a))(R_(39b)), X₄₁ is N or C(R₄₁), X₄₂ is N or C(R₄₂), X₄₃ is N or C(R₄₃), and X₄₄ is N or C(R₄₄), R₁₁ to R₁₄ are each independently the same as described in connection with R₁ in claim 1, and two of R₁₁ to R₁₄ are optionally linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, R₂₁ to R₂₃ are each independently the same as described in connection with R₂ in claim 1, and two of R₂₁ to R₂₃ are optionally linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, R₃₁, R₃₃, R₃₄ to R₃₇, R₃₉, R_(39a), and R_(39b) are each independently the same as described in connection with R₃ in claim 1, and two of R₃₄ to R₃₇ are optionally linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, and R₄₁ to R₄₄ are each independently the same as described in connection with R₄ in claim 1, and two of R₄₁ to R₄₄ are optionally linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group.
 14. The organometallic compound of claim 1, wherein the organometallic compound is represented by one selected from Formulae 1(1) and 1(2):

wherein, in Formulae 1(1) and 1(2), M, X₁ to X₄, Y₁ to Y₉, CY₁ to CY₄, T₁ to T₃, b1 to b3, R₁ to R₄, and a1 to a4 are each independently the same as described in claim 1, X₄₂ is N or C(R₄₂), X₄₃ is N or C(R₄₃), and X₄₄ is N or C(R₄₄), R₄₂ to R₄₄ are each independently the same as described in connection with R₄ in claim 1, and two of R₄₂ to R₄₄ are optionally linked to each other to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, CY₅ and CY₆ are each independently a C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, R₅, and R₆, are each independently the same as described in connection with R₁ claim 1, a51 and a61 are each independently 0, 1, 2, or 3, T₄ is C, Si, or Ge, T₅ is selected from a single bond, *—O—*′, *—S—*′, *—C(R₇)(R₈)—*′, *—C(R₇)═*′, *═C(R₇)—*′, *—C(R₇)═C(R₈)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—Si(R₇)(R₈)—*′, *—Ge(R₇)(R₈)—*′, *—B(R₇)—*′, *—N(R₇)—*′, and *—P(R₈)—*′, R₇ and R₈ are each independently the same as described in connection with R₅ in claim 1, and * and *′ each indicate a binding site to a neighboring atom.
 15. The organometallic compound of claim 1, wherein the organometallic compound is selected from Compounds 1 to 11:


16. An organic light-emitting device comprising: a first electrode; a second electrode; and an organic layer disposed between the first electrode and the second electrode, wherein the organic layer comprises an emission layer, and wherein the organic layer comprises at least one of the organometallic compounds of claim
 1. 17. The organic light-emitting device of claim 16, wherein the first electrode is an anode, the second electrode is a cathode, and the organic layer further comprises a hole transport region disposed between the first electrode and the emission layer and an electron transport region disposed between the emission layer and the second electrode, the hole transport region comprises a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, and the electron transport region comprises a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.
 18. The organic light-emitting device of claim 16, wherein the emission layer comprises the organometallic compound.
 19. The organic light-emitting device of claim 18, wherein the emission layer further comprises a host, and an amount of the host in the emission layer is larger than an amount of the organometallic compound in the emission layer.
 20. A diagnostic composition comprising at least one of the organometallic compounds of claim
 1. 